An EPON which is going on standardization in IEEE 802.3ah, is tree topology consists of a OLT and multiple ONU using passive optical components, so this network is susceptible to variable security threats - eavesdropping, masquerading, denial of service and so on. In this paper, we design a security protocol supporting authentication and confidentiality services in MAC layer in order to prevent these security threats and to guarantee secure data exchange The designed security protocol introduce public-key based authentication and key management protocols for efficient key management, and choose Rijndael algorithm, which is recent standard of AES, to provide the confidentiality of EPON Proposed authentication and key management protocols perform authentication and public-key exchange at a time, and are secure protocols using derived common cipher key by exchanging public random number To implement the designed security protocol, we propose the procedures of authentication and public-key exchange, session key update, key recovery. This proposed protocol is verified using unknown session key, forward secrecy, unknown key-share, key-compromise impersonation

In this paper, we presented the dynamic random access channel allocation method under the priority based scheduling policy in order to improve the system performance of HIPERLAN/2 standardized by ETSI According to the scheduling policy, AP scheduler primarily allocates the resource to the collision MT This scheduling policy bring about decreasing the transmission delay of collision MT Dynamic RCH(random access channel) allocation method decreases the collision probability by increasing the number of RCH slots in case of low traffic. While it increases the maximum throughput by increasing the number of the data transmission slots in case of high traffic Therefore dynamic allocation method of RCH slots decreases the scheduling delay and increases the throughput When we evaluate the performance of presented method based on standards, we saw that the presented method improve the performance of the MAC protocol in terms of throughput and transmission delay

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network PON architecture is very simple but it requires MAC protocol for control of upstream traffic This paper proposes a Request-Counter MAC protocol for a broadband access network using an ATM Passive Optical Network supporting CBR/rtVBR, nrtVBR, UBR and ABR traffic For the proposed MAC scheme, we present Grant Field format, Minislot format, and bandwidth allocation algorithm From the simulation result, we have confirmed that our proposed scheme can reduce the average cell delay in comparison to that of conventional MAC schemes

This paper presents the Genetic Algorithm based Task Scheduling (GATS) method for the scheduling of programs with diverse embedded parallelism types in Distributed Parallel Systems, which consist of a set of loosely coupled parallel and vector machines connected via high speed networks The distributed parallel processing tries to solve computationally intensive problems that have several types of parallelism, on a suite of high performance and parallel machines in a manner that best utilizes the capabilities of each machine. When scheduling in distributed parallel systems, the matching of the parallelism characteristics between tasks and parallel machines rather than load balancing should be carefully handled with the minimization of communication cost in order to obtain more speedup. This paper proposes the based initialization methods for an initial population and the knowledge-based mutation methods to accommodate the parallelism type matching in genetic algorithms

As the recent rapid development of internet technology and the wide spread of multimedia communications, massive increase of network traffic causes some problems such as the lack of network paths and the bad quality of service To resolve these problems, this paper presents a web-based traffic control system which supports QoS of realtime packet transmission for the multimedia communication The traffic control system presented in this paper applies the integrated service model and provides QoS of packet transmission by means of determining the packet transmission rate according to the policies of network manager and the optimal resource allocation considering the end-to-end traffic load It also provides QoS for the realtime packet transmission through the admission controller and the packet scheduler by the modified algorithm support asynchronous and class-based queuing

In the Protocol-Independent Multicast Sparse Mode(PIM-SM), we need a careful selection scheme for the Rendezvous Point(RP) which influences much on the QoS due to the delay among multicast group members and packet loss The QoS based RP selection schemes choose RPs which satisfy the restriction conditions such as bandwidth, delay, and other QoS parameters In this paper, we propose a new RP selection scheme which is a variation of the group-based RP selection scheme The new algorithm, MCT(Maximum Cross Tree), is implemented by taking advantages of the topology-based selection scheme and the group-based selection scheme as well In order to verify the proposed algorithm, we first measure the multicast traffic data of the Virtual Conference System implemented on the IPv6 network via KOREN, then expand the results to two types of network models and analyze the performance by computer simulation.

Conventional command-based communication services are rapidly substituted by multimedia web-based communication services at most recent times As the result, many valuable database and services that were developed by investing lots of human and material resources become to be useless Therefore in this paper we researched the methodologies and techniques for designing and implementing a multimedia web-based database system that made users easily access to database and services by updating the conventional command-based database services

In order to provide seamless wireless Internet service, the basic mobile IP protocol should be enhanced to solve packet loss problem from large registration latency because frequent handoffs occur in cellular networks. In this paper, we suggest a new micro-mobility management protocol based on MPLS while supporting Qos, and evaluate its performance using simulation. We use MPLS label switching techniuqe in cellular access networks to simplify location management and speed up packet transmission. We adopt context transfer procedure to minimize the delay needed to attain prior level of service after handoff Packet loss can be minimized during handoff by transmitting received packets from old BSLER to new BSLER using a spliced LSP between them. Simulation results show that the proposed MPLS-based micro-mobility management protocol provides a seamless handoff and supports QoS of user traffic

As the traffic grows rapidly in the Internet, the QoS guarantee of the flows and the traffic engineering problems have become very important issues. MPLS has more advantages to solve the problems than existing IP routing because of its use of multiple paths between the source and destination pairs Particularly, the availability of Constraint-based Shortest Path First(CSPF) algorithm and explicit route in MPLS made the problem referred above to be solved efficiently. However, the CSPF algorithm has the characteristic of selecting the shortest path of all paths which meet the traffics' QoS constraints Therefore, even though there are alternative paths to route traffic, alternate QoS paths may not be found and best-effort traffic will be dropped during congestion period In this paper, we present the network resource optimization method related to the traffic engineering by using load balancing through routing in MPLS network.

High speed networking applications like video-on-demand require the support of switches that can handle very high multicast loads. Switches studied in the past can support multicast loads of 2530% To overcome this limitation, Tandem Expanded Delta Network(TEDN) multicast switch was proposed to support more higher multicast load by 8590% without degradation in the performance But there is tremendous routing capacity that is not used in the series of routing network blocks. This paper presents modified TEDN multicast switches to save the excessive routing capacity. by recirculating packets in last routing network, we can achieve the acceptable packet loss ratio with the smaller number of routing network blocks. Extensive simulations show that our proposed switches have the acceptable packet loss ratio with reduced hardware cost

As Information Security Technology has become rather transparent, wide, and integrated than in part, exclusive, and separated, A necessity of the study about integrating the separated distributed security systems into one module, has grown However, there is no integrated framework which can manage all separate security systems as one integrated one yet. Accordingly, we propose a new policy based network admirustrative model in this paper which can integrate individual security systems and distributed control way into one effectively

This paper addresses the issue of applying the concept of IT everywhere IT inside to R&D planning system We investigate R&D planning system, mid term IT technology development plan, and the fact and outlook of wireless communications technology in Korea and also focus o deriving core wireless telecommunications technologies and priority setting under R&D planning system, using Analytic Hierarchical Process.